The mixing valve is known that is used in a bathroom or washroom to mix a cold water and a hot water, and is able to regulate a mixing ratio (i.e. water temperature) and a flow rate of the cold and hot waters. In general, such mixing valve comprises a valve seat connected to a cold water tube, a hot water tube and a warm water tube that are laid out in a room. Usually, such mixing valve is operated between two extreme conditions, i.e. a closing position, in which no water flows out through the mixing valve, and a hot-water maximum position of the mixing valve, in which the water has a highest water temperature and a maximum flow rate of hot water, by rotating the handle of the mixing valve in a range between two extreme rotation positions. To improve the performance of the mixing valve, incorporated in a valve core are two check valves for sealing connecting with a cold water outlet and a hot water outlet in the valve seat, respectively, so as to prevent the cold and hot waters from being mixed with or cross flowing to each other before passing through a mix regulating mechanism (such as a valve plate) in the valve core, and further a pressure balancing valve arranged downstream the check valves, so as to balance the pressures of the cold and hot waters flowing into the valve core and to prevent the pressures of the cold water from the cold water tube or of the hot water from being sharply increased to cause sudden increasing or decreasing of the outflow water temperature.
Chinese invention patent CN 101418866B discloses a mixing valve, comprising a valve body (which is actually a valve seat), a cartridge assembly including check valves and a pressure balancing valve, an outer valve assembly for regulating a temperature and a flow rate of a water, a nut collar for retaining the cartridge assembly and the outer valve assembly onto the valve body by means of threaded connection to the valve body, and a handle. The outer valve assembly of such mixing valve comprises a stem connected to the handle, a stem receiver unrotatably connected to the stem and having a stop surface and a valve plate, a cap nested over the stem receiver and having a stop surface configured to engage with the stem receiver to define a clockwise extreme position, a disk unrotatably connected to the stem and having a stop surface, and a stop member nested over the disk and having a stop surface configured to engage with the stop surface of the disk to define a counterclockwise extreme position (hot-water maximum position). When a user opens the mixing valve to the hot-water maximum position by rotating the handle, the torque acting on the stop surface is transferred starting from the handle, via the proximal end (top end) of the stem, the disk at the middle portion of the stem, the stop member and the cap, to the sidewall of the valve body; when the user closes this mixing valve, the operating torque is transferred starting from the handle, via the proximal end of the stem, the stem receiver at the distal end (bottom end) of the stem, and the cap, to the sidewall of the valve body. It can be seen that in such mixing valve, the operating torque has to be transferred through multiple components and has a long path to be transferred, which is disadvantageous in bearing a relatively greater twisting force exerted by the user.
Chinese Utility Model patent CN 202252102U discloses a constant temperature control device to be mounted within a water channel member (i.e. the valve seat of the present invention), comprising a temperature control rod assembly, a fine adjusting mechanism, a check valve, and a pressure balancing valve. When a user opens such constant temperature control device to the hot-water maximum position or closes the device to the closing position, the operating torque applied by the user is transferred starting from the handle, via the temperature control rod, a stop member of the fine adjusting mechanism, the housing of the fine adjusting mechanism, and a lower housing seat, to the valve seat. This arrangement causes that the operating torque to be transferred through an interface between the housing of the fine adjusting mechanism and the lower housing seat having a relatively lower load carrying capacity. Accordingly, it is still disadvantageous in bearing the relatively greater twisting force exerted by the user who typically intends to operate the valve with an excess force.
Chinese Utility Model patent CN201196275Y discloses a cold and hot water control valve configuration for faucet, structurally similar to the configuration disclosed in CN 202252102U, and thus has to suffer the same deficiencies of poor ability to withstand the operating torque applied by the users.
In addition, when the cold and hot water tubes are mounted in a reversed manner, the mixing valve has to be retrofitted to allow the operator to operate the handle in the same direction within the same rotation range. such reversion of cold and hot water tubes exists for example in two adjacent bathrooms at either side of the same wall. In the case that the prior art mixing valve usually has to comprise a separate stop member abutment, when the mixing valve is retrofitted, the stop member abutment and the stop member arranged thereon have to be first detached, then rotated and then re-installed in a different angle position, which increases the labor work of the worker and the risk of mis-installation.
Therefore, there is a need for a mixing valve that provides solution to the problems mentioned above.